Active implantable medical devices (IMDs) can be used to treat a variety of symptoms or diseases. For example, an IMD can be used to generate therapeutic electrostimulation for delivery to one or more tissue sites, such as including one or more cardiovascular or neural targets. Such electrostimulation therapy can include one or more of a cardiac pacing therapy, a cardioversion or defibrillation therapy, a cardiac resynchronization therapy, a neural stimulation therapy that can include, for example, an autonomic modulation therapy (AMT), a neurological disorder therapy, a pain management therapy, or one or more other electrostimulation therapies.
An example of an IMD can include a battery-operated electronics unit implanted under the skin, such as in the pectoral region, electrically and mechanically connected to one or more intravascular leads extending into a heart chamber or one or more coronary blood vessels. The one or more intravascular leads can include one or more electrodes to electrostimulate the heart tissue and sense potentials at the heart tissue (e.g., for sensing intrinsic cardiac activity, or sense an evoked response to the application of electrostimulus).
However, the use of such leads can be precluded in certain circumstances, particularly in blood vessels having limited available cross sectional area, or in portions of the body such as certain heart chambers, where such leads can be contraindicated for chronic implantation due to one or more of a risk of thrombus formation or lead dislodgement.